Event‐driven Process Chain models are a type of flowchart used for business process modeling. They serve a purpose similar to BPMN models in supporting business process improvement by helping to link different views of an enterprise model together. An EPC considers “events” as triggers to or results from a process step; this is useful for modeling complex sets of processes. EPC triggers resulting from a process step are called “functions.” Thus, the flow is normally event‐function‐ event.
Source: Guide to the Business Process Management Body of Knowledge – ABPMP BPM CBOK V3.0.